Effect of stocking density on growth, hematological and biochemical parameters and antioxidant status of silver catfish (Rhamdia quelen) cultured in a biofloc system

Biofloc technology (BFT) is a technique of enhancing water quality, focused on a more efficient use of nutrients and lower water consumption. This technology may result in higher productivity with less impact to the environment. This work aimed to assess the effect of different stocking densities (SD) on growth, hematological and biochemical parameters and antioxidant status of silver catfish (Rhamdia quelen) juveniles cultured in a biofloc system. Three different SDs were used: 10, 20 and 30 g of biomass/L (designated as treatment D10, D20 and D30, respectively). After 45 days, fish from D30 group showed significantly improved growth performance (final weight and daily weight gain) and lower fat deposition in the fillet. Aspartate aminotransferase (AST) levels and superoxide dismutase (SOD) activity were significantly reduced in the liver of silver catfish reared at the higher SD. In addition, fish from D30 group showed the lower values for lipid peroxidation (TBARS) in muscle and gill tissue. These results indicate that an initial SD of 30 g of biomass/L appears appropriate for silver catfish juveniles cultured in a BFT system.